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Thursday, September 23, 2010

6.18a Pacemaker Saves a Life - Read it Here!

Physician's Notebooks 6 - http://physiciansnotebook.blogspot.com - See Homepage


18. Cousin Dan’s Heart Block and Pacemaker, Update 28 Jan. 2018
I made a 2-week trip to New York City, 17 May 2006 and took the D train to last station Norwood in Bronx to see my cousin, Dan. He was born 19 April 1921. Dan and I are the only remaining cousins of our generation.  (Dan died in late 2016 age 95 in nursing home after vegetating a year)
   I have really come to know Dan since I started coming back to Bronx. Dan has interested me because he is one of my case studies in Longevity.
   It is a warm May morning. I approach Dan’s building surprised to see him sitting outside on a folding chair. In past, if he went out in nice weather, he usually walked to nearby park and sat on a bench.
   He looks as usual – thin with sharp face and sparse hair; no younger than his then 85 years, and intelligent.
   “How are you?” I ask.
   “Sometimes better than other times,” he replies with unusual seriousness.
   We talk of literary things. Then Dan recalls my offer to clean his rooms, and wonders if I might do it now.  “The dust is getting to my lungs, and I can’t breathe,” he explains.
The rooms look like no one used a broom in 30 years.
It is possible that uncleaned rooms block breathing. Like coal miner getting lung disease from inhaling dust, a person living in a very dusty flat might develop trouble breathing.  So I roll up sleeves. Wow! Is it dust-laden! I can believe he developed a lung problem from it. But while I am doing the day up in Dan’s, I examine him. I don’t have stethoscope or timepiece. So I start by putting a finger on his wrist.
I am not surprised that Dan’s pulse feels faint. Hardening of arteries does that. But I am surprised at the slow rate. Even without timepiece I can estimate the normal pulse beats per minute, and now Dan's is below 30.
   What cause? The least serious is sinus bradycardia, a normal rhythm but slow beat. In well trained athlete it is sign of healthy heart. But in an 85 year old, who complains of breathing problems? More serious could be atrial fibrillation. It is the most common abnormal heart rhythm. Although not typical, it can show a slow and seemingly regular pulse, even though the actual heartbeat is rapid and irregular, because many of the fibrillation beats are too weak to feel at the wrist. But by listening to the heart in the chest, I could immediately check if Dan had A. fibrillation. 
I do it the old fashioned way, putting my ear against Dan’s chest. And lo! The heartbeat in his chest is the same slow rate as his wrist pulse.
   That means a complete 3rd degree heart block
   To explain: The normal heartbeat is initiated in a small area of electrically active tissue of right atrium (upper heart chamber) and the signal passes down into right and left ventricles and excites the ventricles to contract, which gives the heartbeat. This normal sinus rhythm varies around 70 beats per minute at rest. In complete A-V block, the signal has been interrupted by disease. Thus no signal gets to the ventricles. If the ventricles do not contract, you die. So in your self protection, the ventricles, when they stop receiving the normal signal from above, start to beat independently and the ventricular rhythm gives very slow heartbeat, 30 per minute. And it is a fixed rate; it cannot increase with exercise or other demand on the heart. So after complete A-V block, the moment you try exercise, you faint from lack of oxygen in brain. Even worse, when the heart rate drops below 30, the heart’s ability to squeeze out enough blood to supply the body (cardiac output) is not sufficient even for resting, and you get heart failure and it worsens and if not reversed will lead to death over the next days.
   So first thing after taking my ear away from Dan’s chest I say, “Show me your feet,” and ask, “Have your ankles swelled?”
   Ankles swelling is an early sign of heart failure. I am relieved to see no swelling and to hear, “No.” It suggests that the onset of Dan's heart block must be recent and also that Dan’s heart muscle must be basically healthy (with the exception of the small area of heart block). But the heart block is getting to him in his lungs causing the breathing he notes worst in his bedroom because in bed his head is flat on pillow and this increases congestion in lungs. Also, on questioning, he admits to fatigue.
   It is important to keep in mind that Dan was 85 and did not move much. Ironically, this saves him from serious heart failure. But I realize Dan is on the edge. His heart block for the moment only affects his breathing and saps his energy. But with such a slow heart rate, in a day or two he will go into more serious heart failure. 
The electric cardiac pacemaker made a new dawn. Where before, a complete heart block meant inevitable premature death; now it can be reversed by rapid diagnosis and restoring a timely heartbeat.
   Understanding an interruption of signal between atrium and ventricle helps one to see how the pacemaker solves the problem by replacing the natural heart tissue-connection with a metal wire that connects an artificial heartbeat signal emitter with the ventricle by terminals at the end of the wire. The pacemaker is inserted through a big vein into the chest. It has a pulse generator and battery that is implanted under the skin in soft tissue of the chest wall. The pulse generator is a minicomputer: to and from it run wire-leads from the right atrium and the ventricles of the heart, which feed it information from the heart that may modify its program of artificial heartbeat signal. The command-lead that initiates the pacemaker heartbeat goes from the pulse generator in a wire that runs in the vein into the right side of the heart and, depending on the purpose and type of pacemaker, is implanted by a hook anchor inside of the right atrium and another in the apex of the right ventricle. The battery, which should last 7 to 12 years, can be, by minor surgery, replaced before it runs down.
   Once a pacemaker is in place, the heart-block patient’s heart rate can be set to the normal 70 per minute and also the pacemaker may have a sensing mechanism that allows it to increase the heartbeat rate as necessary when the patient needs an increase of cardiac output due to work or other exercise. 
I explain to Dan, and without leaning on a panic button suggest we go to the emergency room and let them do an EKG and go from there. 
   Dan agrees. It takes us 30 minutes. The ER waiting room is filled. The system is you sign a book and you are served in order of arrival; if serious symptom, immediately. 
Keep in mind: Dan shows no external sign of emergency. He is old, he is frail, he is slow; but no obvious distress. 
So I tell a lie and a truth. I walk into the ER doctors’ room and say, “I just brought in my 85-year-old cousin. He has chest pain and rate is 30 per minute.”
That gets everyone moving.
   Within the next hour Dan has an EKG that confirms complete A-V block and an Echocardiogram that shows his heart muscle strong and his heart mechanism including valves OK, except for the heart block. The ER physician then explains the pacemaker to Dan, and I advise Dan to sign permission, and he is taken to a room and – Voila! – his problem solved with insertion of pacemaker. 
It is now 3 hours from arrival. Dan got his pacemaker and his pulse is strong and heartbeat rate 72 per min and he feels better. The doc asks if Dan would prefer to stay overnight. Dan says No and we walk home.
   
Postscript: Up till his death 10 years later, Dan did not needed one pill for his heart. 
 (Chapter continues. Section that follows tells about pacemakers as of 2016. To read it now, click 6.18b Pacemakers - Technique Insertion/Complicati...









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